Cartilage Pathology With Concomitant Ankle Instability

Cartilage Pathology With Concomitant Ankle Instability George H. Smith, MMedSci, FRCS (Orth),* Nicola Maffulli, MD, MS, PhD, FRCP, FRCS (Orth), FFSEM,† and James D. Calder, TD, MD, FRCS (Orth), FFSEM‡,§ Ankle instability and chondral pathology commonly present together. This review discusses the current evidence for the etiology of chondral lesions, the association between ankle instability and chondral injury, and the optimal method of managing a patient with symptomatic chondral pathology (osteochondral lesions and tibiotalar osteoarthritis) in the setting of an unstable ankle. The literature pool is weak for recommendations on the management of osteophytes and osteoarthritis with ankle instability. Multiple factors do compound dual treatment of osteochondral lesions and instability; however, concomitant surgery addressing both pathologies has been shown to have outcomes comparable to osteochondral surgery alone with similar complication rates. Oper Tech Orthop 24:152-156 C 2014 Elsevier Inc. All rights reserved. KEYWORDS chondral injury, cartilage pathology, osteochondral lesion, ankle instability, surgical outcome

Introduction

T

he recent advances and popularization of ankle arthroscopy has brought the opportunity to treat a broader and forever expanding array of foot and ankle conditions. Scientific literature is not yet available, however, to specifically support certain procedures or combinations of procedures, particularly those that are new and innovative.1 The outcomes for ankle instability surgery are well documented and tend to demonstrate good-to-excellent long-term results.2,3 Equivalent outcome scores are not universally achieved with surgery for osteochondral lesions (OCLs) but remain satisfactory.4 To date, there is no consensus on the optimal method of managing a patient with the combination of a cartilage lesion and an unstable ankle.5-9 This article reviews the background to the problem and discuss the pertinent current literature. *Norfolk and Norwich University Hospital NHS Trust, Norwich, UK. †Queen Mary University of London, Centre for Sports and Exercise Medicine, Mile End Hospital, London, UK. ‡Department of Orthopaedic Surgery, Chelsea & Westminster Hospital, London, UK. §The Fortius Clinic, London, UK. Address reprint requests to James D. Calder, TD, MD, FRCS (Orth), FFSEM, Department of Orthopaedic Surgery, Chelsea & Westminster Hospital, 369 Fulham Rd, London, UK. E-mail: [email protected]

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http://dx.doi.org/10.1053/j.oto.2014.04.001 1048-6666//& 2014 Elsevier Inc. All rights reserved.

Ankle Instability Ankle instability is a subjective sensation of the ankle “giving way.” It can occur in lateral, medial, torsional, and translational ankle movements. The most common cause is an inversion ankle injury with an associated tear to the lateral ligament complex leading to chronic lateral ligament laxity.10-13 Ankle sprains occur in an estimated 628,000 Americans every year.14 Current literature predicts 10%-20% of these patients will develop chronic lateral instability symptoms,13,15 and 20%40% are likely to develop chronic pain.16 In athletes, the figure is substantially worse, with 21%-80% reporting chronic symptoms after an ankle sprain.13,17,18 The 2 most common symptoms after an ankle sprain in a study of 380 athletes from Hong Kong18 were pain (30%) and instability (20%). The pathomechanics of ankle instability has been well described by Bonnel et al.19 The cause for the chronic pain, however, is widely debated. OCLs, osteoarthritis, soft tissue impingement, tendinopathy, and loose bodies are all commonly seen in patients with chronic instability.9

Etiology of OCLs OCL is a broad term that encompasses any injury to the chondral surface. Such injuries include the historical term osteochondritis dessicans as well as osteochondral fracture and

Cartilage pathology with concomitant ankle instability osteochondral defect. They were initially described by Konig.20 OCLs of the ankle joint typically present as pain, stiffness, and swelling in the young adult.21 Up to 50% of patients have a cartilage injury or a bone bruise after an ankle sprain.22-24 Does this chondral injury, however, lead to the development of an OCL? A review by McCollum et al25 noted that the natural history of most bone bruises is benign, but the integrity of the subchondral bone plate is critical to the resolution or possible propagation to an OCL. Previous authors have noted many OCLs develop without any history of trauma.26-28 In a review of 582 patients with talar OCLs,28 66% had a history of ankle trauma, whereas 34% did not. This is similar to the 64% traumatic rate seen in the inaugural OCL series by Wagoner and Cohn.29 In the study by Tol et al,28 56% of the lesions were found on the medial talar dome and 44% on the lateral, with trauma implicated in 94% and 62% of cases, respectively. The literature demonstrates a clear association between OCLs and ankle injuries. The etiology of OCL in patients without a history of trauma (spontaneous), however, remains uncertain.30 The repetitive microtrauma seen with ankle instability has been postulated to play a role.31,32 The evidence indicates that although there does appear to be a correlation between ankle injury and chondral injury, there is a distinct patient group who will have no history of trauma.

Ankle Instability and Chondral Injury Several studies have noted an association between ankle instability and chondral injury albeit with a wide variation in rates from 23%-95%.7,8,33 Taga et al34 demonstrated chondral lesions in 95% of patients undergoing lateral ligament reconstruction. Of these the medial tibial plafond was the most common site (33%), which also saw most higher grade lesions. The suggestion that the medial part of the tibiotalar joint is more susceptible to injury because of instability was reaffirmed by others.9,33,35 However, Gregush and Ferkel6 noted lateral lesions (61%) were more common in their study of 31 ankles undergoing lateral ligament reconstruction. Biomechanical data support the increased occurrence of pathology seen on the medial side. For example, lateral ankle ligament disruption has been shown to increase both anterior translation and internal rotation of the talus.36-38 Theoretically, this should cause medial abutment and abnormal cartilage strain between the talus and the medial malleolus.39 Bischof et al40 used a 3-dimensional magnetic resonance imaging model and biplanar fluoroscopy to evaluate in vivo cartilage contact strains in 7 patients with lateral ankle instability. They demonstrated that with an unstable ankle the peak strain increased (21%-29% of body weight) and the location shifted in both anterior (15.5 mm) and medial (12.9 mm) directions. Taga et al34 demonstrated a link between the chronicity of the instability and the risk of chondral injury, suggesting a causative association. This prompted the authors to recommend surgical repair of the lateral ligament complex to avoid further damage. Valderrabano et al41 confirmed the high rate of cartilage lesions (81%) seen at long-term (12 years) follow-up of unstable ankles thereby adding weight to the prophylactic

153 fixation theory of Taga et al.34 The severity of chondral lesions and the duration of instability were questioned by both Sugimoto et al42 and Okuda et al.33 Under arthroscopic examination, Sugimoto et al42 found no correlation (P ¼ 0.16) between the duration of instability symptoms and severity of chondral damage. With no power analysis and a clear trend between increasing severity and duration of symptoms (mean of 41 weeks for the least severe chondral damage and 104 for the most severe), one could question the sensitivity of this study and thus the validity of their conclusion. Okuda et al33 also found no correlation between instability and severity of chondral lesions in a study of 30 ankles with a mean of 70 months from injury to surgery. However, the time interval between the primary injury and surgery was more than 3 years longer for the patient group found with OCLs than those without. There is stronger evidence supporting the association between the duration of ankle instability and presence of chondral injury. Does the chondral location or association with trauma affect the outcome in the unstable ankle? Okuda et al33 demonstrated that focal chondral lesions associated with trauma and instability can, in some instances, do well with ankle stabilization alone. However, whether these OCLs were traumatic or spontaneous in the setting of an unrelated ankle injury is impossible to say. Indeed the role and timing of prophylactic instability surgery is as yet uncertain.

The Management of Ankle Instability With an OCL Independent of each other, the documented outcomes of surgery for OCLs and instability are different. The outcomes for the many described lateral ankle instability procedures are consistently 90%-95% good to excellent.43 The same however has not been reported for OCL surgery.44 The longest followup to date (12 years) of talar OCL treated by bone marrow stimulation21 showed a subjective outcome of “good” to “excellent” in 74%-78% of 50 patients. To date, no studies have investigated the outcome of staged operations. There are however 5 studies5-10 that assessed patient outcomes after concomitant ankle instability and OCL treatment (Table). In total, these studies represent data from 155 ankles. They all share similar protocols for the management of the OCL (bone marrow stimulation), but variable techniques for reconstructing the lateral ligament are complex. The postoperative regimes were also similar with all ankles immobilized, and they advised reduced or non–weight bearing for a period of 3-4 weeks. The return to sport duration was commented on by 2 studies9,6 at 3-4 months and 4-6 months, respectively. The outcomes from these 5 studies were generally satisfactory and similar to previously published data on outcomes after OCL treatment without the additional lateral ligament reconstruction.6 The one anomaly is the article by Choi et al8 who found 11 of 15 patients had an “unsatisfactory” outcome (KarlssonPeterson Ankle Score [KPAS] score o90) after lateral ligament reconstruction and bone marrow stimulation. A KPAS score of

G.H. Smith et al.

154 Table Outcomes of Simultaneous Surgery for Ankle Instability and Osteochondral Lesions (OCL)

Ankles

Followup (Months)

Komenda et al

55

10

Takao et al5

69

Choi et al8

Postoperative Management

Rate of OCL

3-4/52 BKNWB and 3-4/12 RTS 4/52 BKNWB and 8/52 passive ROM

9/55

24

Brostrom Gould Gracillus

69/69

BMS ⫾ debridement

65

29

Brostrom

4/52 BKPWB

15/65

BMS

Hua et al7

81

29

Brostrom Gould

4/52 NWB and 6/52 cast

31/81

Debridement ⫾ BMS

Gregush et al6

31

88

Brostrom Gould (8 Evans and 2 Gracilis)

3/52 BKNWB, FWB at 6/52, and RTS 4-6/12

31/31

BMS debridement if loose flap

References 9

Recon

Treatment of OCL BMS

Outcome 5 Excellent, 4 good, 0 fair, and 0 poor Drilling without debridement, mean ¼ AOFAS 58-93. Drilling and debridement 52-96 KPAS 4 patients 480 (satisfactory) and 11 patients o80 (unsatisfactory) Mean AOFAS 45 preoperative to 81 postoperative for chondral injury (47-90 without chondral injury P o 0.05) 13 patients with preoperative and postoperative AHS 7591, respectively; SANE 86; Weber 85; AHS 89; and B&H 74% good, 23 fair, and 3 poor

AHS, Ankle and Hindfoot Score; AOFAS, American Orthopaedic Foot and Ankle Score; B&H, Berndt and Hardy; BKN/FWB, below knee non-/full weight bearing; BKPWB, Below Knee Plaster and Partial Weight Bearing; BMS, bone marrow stimulation; ROM, range of movement; RTS, return to sport, SANE, Single Assessment Numeric Evaluation.

88 is achieved by a patient who has no pain, can manage the preinjury sporting activities wearing a brace but gets some swelling after exercise, and has 1 episode of instability a year. One might question the arbitrary level at which satisfaction was deemed achieved in this study. Without this subgroup’s individual scores documented, it is impossible to draw any firm conclusions from this study. The complication rates were in keeping with the documented rates for both ankle arthroscopy45 and lateral ligament reconstruction.46 Theoretically, there are some drawbacks to the concurrent management of a patient with a symptomatic OCL and instability. From a practical standpoint, combining arthroscopy and lateral ligament reconstruction leads to longer surgical time. Some argue extravasation of the arthroscopy fluid makes the lateral ligament repair more difficult. Historically, the recovery and rehabilitation are also different for the 2 operations. A single operation has the benefits, however, of a single episode of recovery, the opportunity to improve pain and function from both pathologies, and greater visualization of intraarticular pathology. Ferkel and Chams2 demonstrated only 20% of ankle pathologies seen at arthroscopy could be seen at the subsequent open ligament reconstruction. The management of an asymptomatic OCL and lateral ligament instability is contentious. Okuda et al33 arthroscopically assessed 30 ankles at the time of lateral ligament reconstruction and found 19 had focal chondral ankle lesions. All these lesions were managed conservatively. Outcomes at a

mean of 38 months for ankles with and without chondral lesions were 98 of 100 and 99 of 100 (KPAS), respectively. This contradicts the systematic review by Verhagen et al47 which only found a 45% success rate for nonoperative treatment. This was, however, a small study with no documentation of lesion size. It assessed chondral lesions by an ambiguous grading system and had 7 ankles that had pain with exercise but still had a “good” outcome with a KPAS score of 95 of 100. The study did, however, show that some OCLs can be successfully managed conservatively at the time of ligament reconstruction. The key to a good outcome is to distinguish between an OCL that is symptomatic and one that is an incidental finding in the setting of concomitant pathology. The identification of these patients is an area ripe for further investigation. The question of what to do with a symptomatic OCL in a patient in whom there is clinical laxity despite lack of instability symptoms is also yet to be answered.

Ankle Instability and Osteoarthritis Chondral injuries in the form of osteophytes are commonly seen in the unstable ankle. Overall, 57% were seen at reconstructive surgery by Scranton et al.48 The sporting population is more prone to ankle instability and chondral injuries independent of each other, so drawing a nonbiased causative association between the 2 is difficult. Many authors have, however, shown associations between instability and ankle arthritis.41,49-51 Epidemiologic studies estimate 15% of

Cartilage pathology with concomitant ankle instability end-stage tibiotalar arthritis is because of ankle instability.52,53 To date, one of the longest follow-up studies (13 years) of 310 surgically treated patients with ankle instability54 found the rate of osteoarthritis at approximately 3%. The authors concluded the reduction in arthritis may represent a protective role of ankle instability surgery. Tourné et al55 also found no deterioration in the articular surface of 150 unstable ankles managed by lateral ligament reconstruction after 11 years of follow-up. Although these studies show promising results for “prophylactic” stabilization, more robust studies are required before any recommendations. The combination of established arthritis and ankle instability has been examined by a series of authors.50,56 Harrington50 noted 82% of patients with arthritis at the time of ligament reconstruction described symptom improvement after surgery. Sammarco and DiRaimondo56 reported on 9 patients with ankle instability and osteoarthritis undergoing surgical correction of the instability with a split peroneus tendon graft and no treatment for the arthritis. With subjective assessments, 3 had an “excellent” outcome, and the remaining 6 were deemed “good.” Takao et al57 assessed 7 ankles with instability, and Takakura grade58 stage 2 varus osteoarthritis of the ankle (narrowing of the medial joint space, sclerosis, and osteophytes). They performed arthroscopic drilling of the cartilage defect with lateral ligament reconstruction and found marked improvements in American Orthopaedic Foot and Ankle Score (mean ¼ 42.5-87.4) and cartilage appearance on arthroscopic examination at 1 year after operation. As demonstrated, the literature pool is small for this combination of pathologies and as such caution should be taken before drawing a definitive conclusion. Tibiotalar varus malalignment and instability has been shown to be associated with the development of chondral injury and subsequent arthritis. Valderrabano et al41 found 52% of patients with end-stage ligamentous ankle arthritis had associated varus hindfoot malalignment. In an arthroscopic examination of 99 ankles with recurrent lateral ligament instability, Sugimoto et al42 found varus inclination was significantly associated with more severe chondral changes. The effect of hindfoot malalignment on the long-term outcome of OCL and instability surgery is an area yet to be examined.

Key Points The literature supports an increased rate of both OCLs and osteoarthritis in unstable ankles over time. This is of particular importance in the consent process. The role of surgery to stabilize the ankle to prevent either condition is as yet, however, unanswered. Concomitant instability and bone marrow stimulation surgery provides a dual approach, with satisfactory clinical outcomes for OCLs. Complication rates do not appear dissimilar to those previously reported for isolated OCL or instability surgery.

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